Process for the preparation of cyclomatic manganese tricarbonyls



United States Patent PROCESS FOR THE PREPARATION OF CYCLO- MATIC MANGANESE TRICARBONYLS Hymin Shapiro, East Baton Rouge Parish, La., and

Earl G. De Witt, Royal Oak, and Jerome E. Brown, Detroit, Mich, assignors to Ethyl Corporation, New York, N.Y., a corporation of Delaware No Drawing. ()riginal application July 11, 1955, Serial No. 521,364, now Patent No. 2,818,417, dated Decemher 31, 1957. Divided and this application June 19, 1957, Serial No. 666,743

6 Claims. (Cl. 260-429) The instant invention relates to a broad class of novel organometallic compounds and processes for their manufacture. More particularly, the present invention relates filed December 10, 1952, entitled Cyclomatic Compounds, now Patent 2,818,416.

As will be apparent from the discussion hereinafter the metallic cyclomatic compounds of the present invention comprising a novel class of organometalliccompounds have properties which render them of particular utility as additives. In the preparation of organometallic compounds for such use the properties of stability, volatility, and solubility are of considerable importance. Stability is important in the synthesis and storage of the compounds because additives having low stabilities often decompose in the presence of water, atmospheric constituents such as oxygen and carbon dioxide, and other gases frequently encountered such as sulfur dioxide and hydrogen sulfide. The importance of thermal stability becomes apparent from the fact that the resulting fuel or lubricant compositions frequently encounter diverse conditions of temperature such as those prevalent in tropic, temperate and arctic regions, as well as seasonal fluctuations in temperature in a specific region. Solubility is of considerable importance for ease of blending and in obtaining homogeneous compositions which remain compatible during long periods of storage. The importance of volatility is apparent froma consideration of the fact that volatility has considerable influence on engine inductibility, that is the character of a fuel compoistion to readily undergo operations such as carburetion, manifolding and injection utilized to introduce or induct such compositions into internal combustion engines.

But for a few noteworthy substances, such as tetraethyllead and iron carbonyl, the state of the art has not advanced sufiiciently to permit the preparationand isolation of tailor made organometallic substances having the necessary characteristics of stability, volatility, and solubility. It is evident, therefore, thatthe state of the art will begreatly enhanced by providing a class of organometallic compounds capable of being modified to meet the requirements of fuel and oil additives. Like: wise, a noteworthy contribution to the art will be a method for the preparation of such compounds. 7

-It is, therefore, an object of this invention to provide as new compositions of matter a novel class of organometallic compounds. Likewise, itis an object of this invention to provide processes for the preparation of these new compositions of matter. An additional object of the present invention is to provide a class of metallic cyclomatic compounds of particular utility as fuel additives.

It is also an object of this invention to provide anti knock agents, and fluids and fuels containing the same which possess greatly reduced wear-causing character? istics. It is a further object of our invention to provide fuels suitable for use in high efliciency spark ignition in-.

ternal combustion engines requiring a fuel of high antiknock quality. A further object of this invention is to,

provide means for operating an internal combustion engine on a fuel containing mixtures of antiknock additives in a manner wherein the advantages of the anti knock are utilized to a maximum degree with a minimum of deleterious effect. Further objects of our invention will be apparent from the discussion which follows.

The above and other objects of our invention are accomplished by providing novel hydrocarbon cyclomatic manganese tricarbonyl compounds, as well as lubricating oils, antiknock fluids, and hydrocarbon fuels containing these new compounds in small amounts sufiicient to improve the engine operating characteristics, antiknock properties, and combustion characteristics of said fuels, oils and fluids.

The hydrocarbon cyclomatic manganese tricarbonyl compounds of our invention have the general formula AMn(CO) wherein A is a cyclomatic hydrocarbon radical having from 5 to 17 or more carbon atoms which embodies a group of 5 carbons having the configuration found in cyclopentadiene, said compounds being further characterized in that the cyclomatic hydrocarbon radical is bonded to the manganese by carbon-to-manganese bonds through carbons of the cyclopentadienyl group. The novel compounds as a whole have a total of from 8 to 20 or more carbon atoms. It is found that our new compounds have the most desirable solubility characteristics for use as additives in hydrocarbon fuels. A preferred group of compounds of this invention are those having from 8 to about 16 carbon atoms, as these are found to have the 7 best inductibility characteristics when used in fuels multicylinder engines.

When employing the compounds of our invention as fuel additives, we especially prefer compounds in which at least one of the carbon-to-carbon double bonds in the cyclopentadienyl group configuration is olefinic in nature. In other words, in this preferred embodiment not more than 2 carbons of the cyclopentadiene ring should be shared with an aromatic ring such as a benzene ring. An example of a compound of this preferred embodiment is the indenyl radical additives including other antiknock additives such as,

for example, tetraethyllead. Our additives can be added directly to the fuelin the pure form; or they can be first blended with other components such as scavengers, solvents, antioxidants, etc., into concentrated fluids and Patented Aug. 4,- 1959 these fluids may then be added in the required amounts to fuels to obtain the finished fuel having an enhanced antiknock quality. When our additives are employed in fuels as, for example, in hydrocarbon fuels of the gasoline boiling range, the amount employed per gallon of fuel varies depending onthe enhancement quality desired; Thus, the amount can range from about 0.015 to about 10 "grams of manganese per gallon of fuel in the form of a compound of this invention. When our novel compounds are employed in amounts equivalent to 0.015 gram-of manganese per gallon of fuel, an enhancement in the antiknock value of the fuel is observedover that of the clear fuel. Concentrations of our additives equivalent to amounts greater than 10 grams of manganesev per gallon can also be used, however, because of the extreme antikno'ck effectiveness of our compounds, it is usually not necessary to go above this figure, A preferred range' of concentrations of our compounds inhydrocarbon' fuels is from about 0.03 toabout 6 grams of manganese per gallon as it is seldom necessary to go beyond these limits to obtain excellent antiknock effect.

The antiknock enhancement provided by the compounds of this invention is illustrated by the following results. When manganese in the form of methylcyclopentadienyl manganese tricarbo'nyl, a new compound of this invention, is added to a commercial fuel having an initial boiling point (IBP). of 94 F. and a. final boiling point (FB'P) of 390? .F. in' concentrations equivalent to one gram of manganese per gallon of fuel, the antiknock quality of the fuel, as determined by rating in a standard CPR. single-cylinder knock test engine according to ASTM test procedure D-908 l, is increased from- 83.1 to 92.3' octane number units. To obtain the same increase with tetraethyllead in antiklnockquality would require 3.22 grams: of lead per gallon. 'Ihus, manganese in the form of ourcompounds is 322. percent as eifective as lead in the form of tetraethyllead in increasing the octane value of hydrocarbon fuels.

When one gram of manganese in the form of cyclopentadienyl manganese tricarbonyl is added per gallon of a commercial fuel having. an IBP of 112 C. and an FBP of 3 18 C. and containing 3.13 grams of lead per gallon in the form of tetraethyllead, the increase in antiknock. value isfrom 98.5to 114.0 octane number units, or an increase of 15.5 octane numbers. To obtain this increase with leadwould require an additional 7 grams of'lead per gallon as tetraethyllead. Thus, manganese in the form of the compounds of this invention is as much as 700 percent as efiective an antiknock as lead in the form of tetraethyllead when added to a fuel already containing. 3.13 grams of lead per gallon.

When a commercial fuel having anIBP of 90 F. and an FBP of 406 F. containing 1.59 grams of lead per gallon as tetraethyllead is used in the operation of a multicylinder engine and the octane value determined by the modified borderline rating technique at 2000 rpm. as described below, it is found that 1.26 grams of manganese per gallon in the form of methylcyclopentadienyl manganese trica'rbonyl increases the antiknock value by 7.4 octane numbers. It has been found, however, that when 1.26 grams of iron per gallon in the form of iron pentacarbonyl is employed in a commercial fuel containing. 0.53 gram of-lead per gallon in the form of tetraethyllead and having an octane number of 91.4, the octane quality of the fuel is increased to 94 octane numbers, an increase of 2 .5 octane number units only, as determined in a multicylinder engine operated at a speed of 1750 r.p.m. Thus, the compounds of this invention are at least 296 percent as efiective as iron carbonyl when employed in leaded commercial fuels in multicylinder engines.

Reference to the generic formula described hereinabove indicates that there are three primary constituents in the new compositions. of matter of the present invention. These are first the cyclomatic constituent A, second in. antiknock the metallic constituent Mn, and third the electron donating group CO.

The primary constituent of the new compositions of matter of the present invention designated by the symbol A in the general formula presented hcreinbefore comprises a cyclomatic radical, that is, a cyclopentadienc-type radical which is a radical containing the cyclopentadienyl moiety. In general, such cyclomatic groups can be represented by the four generic formulae presented here-- inafter.

When. a; cyclomatic radical of the compounds of our invention is substituted with univalent aliphatic radicals, these substituents can be a radical selected from the group consisting of alkyl, alkenyl,. aralkyl and aralkenyl. Thus, when these substitucnts are univalent aliphatic radicals they can be alkyl radicals, suchas methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, n-amyl, the various positional isomers thereof as, for example, 2-methylbutyl, 1,1-dimethylpropyl, l-et hylpropyl, and the corresponding straight and branched chain isomers of hexyl, heptyl, octyl, nonyl dccyl, undecyl, dodecyl, tetradecyhhexadecyl, nondecyl, eicosyland the like. Likewise, the univalent aliphatic substituent can be an alkenyl radical, such as ethenyl .d -propenyl, A?-propenyl, isopropenyl, A -buten yl, A bute'nyl, A -butenyl, and the branched chain isomers thereof as A -isobutenyl,- A -isobutenyl, A -sec-butenyl, A -sec-b ute nyl, A -pentenyl, A -pentenyl, and the branched chain isomers thereof- A -hexenyl, A -hexenyl, A hexenyl, andthe branched chain isomers thereof, including 3,3-dimethyl-A -butcnyl; 2,3-dimethyl-A -butenyl; and l-methyll-ethyl-A -propenyl; and the various isomers of heptenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tetra decenyl, heptadecenyl, octodecenyl, eicosenyl, and the like.

When the organic radicalsubstituted in the cyclomatic group is a univalent aliphatic radical, it can be an aralkyl radical such as, for example, benzyl, a-phenylethyl, j3-phenylcthyl, a-phenylpropyl, fi-phenylpropyl, a-phcnylisopropyl, a-phenylbutyl, a-phcnyli sobutyl, e-phenyl-tbutyl, aU-naphthylmethyl, c naphthylmethyl, a-(aT-naphthyl) -ethyl, /8-( a-naphthyl) -ethyl, a-( a-naphthyl-) -propyl,- a-(B'maphthyI)-isopropyl, 'y-(a'-naphthyl)-butyl, o -(ofnaphthyl-Hsobutyl, fi-(e naphthyl)-sec-butyl, the corresponding atand fimaphthyl derivatives of n-amyl and the various positional isomers thereof, and the like. Other sucharalkyl radicals include the a, ;8-, and- 'y'anthryl derivatives of alkyl radicals such as a'-anthrylmethyl, fl-(f-anthryD-ethyl, A-(fl-anthryl)-2-methylamyl, and the like, and the corresponding alkyl derivatives of phenanthrene, fluorene, acenaphthlene, chrysene, pyrene, triphenylene, naphthacene, etc.- The univalent aliphatic radical can be antaralkenyl: radical such as nt-phenyl ethenyl, p-phenylethenyl, a-phenyl, A -propenyl, and the phenyl derivatives of. the isomers of butenyl, pentenyl, heptcnyl, and the11ike,.up to about eicosenyl. Other such arylalkenyls include a- (.a-naphthyl)-ethenyl, oe-(fi naphthyl=):-ethenyl, a-(d-naphthyl -A -pr openyl, az-(.a='-napl:t

, thyl).-A -propenyl-',. a-(fi -naphthyl)-isopropenyl,. and the like. In addition, such aromatic derivatives of alkcnyls, that is, aralkenyl radicals include derivatives of phen'anthrene, fluorene, acenaphthene, chrysene, naphthacene, and the like.

- When theorgani'c' radicals comprising the subs-tituc'nts' in thecyclomatic; groups of the compounds of our invention are univalent alicyclic radicals, thesegcan be radicals selected from the .group' consisting of cyclo 'alkyl and cycloalkenyl radicals. Thus, such univalent alicyclic radicals can be cycloal'kyl radicals. such as, to: example, cycl'opropyl cyclobnt'yl, cycloamyl cyclohexyl, cyclononyl, cyclodecyl cyclododecyl', cyclooctodec'yl, eycloeicosyl, andsuch cycloaliphatic radicals as a-cyclopropyletliyl, w-cycl'obutyl ropyl, and the like; Similarly, the alicyclic radical su-bsti'tuents can be cycloalk'enyl radioals such as a-cyclohexyl-othenyl, a-cycloheptyl-N-propenyl, 'fi-cyclooctyl-n -propenyl, a-methylene-p-cyclododecylethyl, and the like.

When the organic radicals substituted in the cyclomatic groups of our compounds are univalent aromatic radicals, theycan be selected from the group consisting of aryl and *alkaryl radicals. Thus, these univalent aromatic radicals can be aryl radicals such as, for example, phenyl, naphthyl, anthryl, and the like, including the various monovalent radicals of such aromatics as indene, acenaphthene, fluorene, naphthacene, ch-rysene, and the like. Moreover, these univalen-t aromatic radicals can be alkasryl radicals such as, for example, tolyl, 3,5-xylyl, p-cumenyl, mesityl, ethylphenyl, Z-methyl-anaphthyl, l-ethyLB-naphthyl, and the like.

' Having amply described the meaning of the term organic radical, the discussion with regard to cyclom-atic radicals has been facilitated. As stated hereinabove, the cyclornartic groups of the compounds of the present invention can be represented by four general formulae. The first class of cyclomatic radicals can be represented by the general formula wherein each of R R R R and R can be the same or different :andis selected from the group consisting of hydrogen and organic or hydrocarbon radicals having from about 1 to about 12 or more carbon atoms. 11- lustr'ative examples of such cyclomatic radicals include cyclopentadienyl; l-methylcyclopentadienyl; 2,3-dimethyl-cyclopent-adienyl; S-ethylcyclopentadienyl; l,3,4-tripropylcyclopentadienyl; 1,5-dipentylcyclopentadienyl; 2- m ethyl-4-tbutylcyclopentadienyl; 3-isopropeny1cyclopentadienyl; 3,4-di(A -isobu-tenyl)-cyciopentadienyl; S-methyl-S -(-A -pentenyl) -cyclopentadienyl; 3- fi-phenylethyl) c'yclopentadienyl; 3-cyclohexylcyclopentadienyl; 2-phenylcyclopentadienyl; 1-ethyl-3-( a-methyl) -cyclopentadienyl;

2-(o-tolyl-cyclopentadienyl; l-acetylcyclopentadienyl; and

the like. I

The second type of cyclomatic radical is the indenyltype radical represented by the general formula R 3 I 4 R, 2 6

B II

R1 HI wherein each of R R R5, R R R R R3 and R;

can be the same or diiferent and is selected from the wherein a and b can be the same or different and are small whole integers including 0 and excluding l, the sum a|b being atleast 2, and wherein R is selected from the class consisting of hydrogen and organic radi cals. Thus, when a is zero each of the carbon atoms designated as 2 and 3 have attached thereto a monovalent radical selected from the class consisting of hydrogen and organic radicals. Furthermore, the monovalent radicals so attached can be the same or different. The same discussion applies to each of the carbon atomsdesignated as 4 and 5 when b is zero. Illustrative examples of this type of cyclomatic radical include 4,5,6,7- tetrahydroindenyl; 1,2,3,4,5,6,7,8-octahydrofluorenyl; 3-' methyl-4,5,6,7-tetrahydroindenyl; and the like.

The third primary constituent of the new compositions of matter of the present invention is an electron donating group, namely, CO. I

Non-limiting examples of the compounds of this invention in which the cyclomatic radical has the configuration shown in structure I above are ccyclopentadienyl manganese tricarbonyl; methylcyclopentadienyl manganese tricarbonyl; ethylcyclopentadienyl-manganese tricarbonyl; propylcyclopentadienyl manganese tricarbonyl; butenylcyclopentadienyl manganese tricarbonyl;- tert-butylcyclopentadienyl manganese tricarbonyl; hexylcyclopentadienyl manganese tricarbonyl; cyclohexylcyclopentadienyl manganese tricarbonyl; heptylcyclopentadienyl manganese tricarbonyl; decylcyclopentadienyl manganese tricarbonyl; dodecylcyclopentadienyl manganese tricarbonyl; l,2,3,4-tetramethylcyclopentadienyl manganese tricarbonyl; l,2,3,4,5 pentamethylcyclopentadienyl manganese tricarbonyl; 1,3-dibutylcyclcpentadieny1 manganese tricarbonyl; 1,2-dipropyl-3-cyclohexylcyclopentadicnyl manganese tricarbonyl; tolylcyclopentadienyl man ganese tricarbonyl; 1,3-diphenylcyclopentadienyl manga nese tricarbonyl; acetylcyclopentadienyl manganese tricarbonyl; and the like.

When there is only one organo or hydrocarbo substitu-' cut on the cyclopentadienyl ring, its position is not speci fied since, according to theory, the cyclopeutadienyl ring or group is bonded to the manganese by five equivalent bonds running from each of the five carbons in the cyclepentadienyl ring to the manganese. Since all these bonds are equivalent and all five carbons in the ring are equidistant from the manganese, it is immaterial'to; whichof the five carbons a single substituent isfattached." When, however, more than one substituent is attached to the cyclopentadienyl ring, the positions are given so as toindicate' the relative positions of the different sub, stituents with respect to each other on the cyclop entadi enyl ring. 7

Examples of compounds having the configuration of structure 11- givenhereinabove are indenyl manganese tricarbonyl; 3-methylindenyl manganese tricarbonyl; -3-eth-' enylindenyt manganese tn'carbonyl; 2,3-dimethylindenyl manganese tricarbonyl; l,3-diethylindenyl manganese tncarbonyl" 1,7- diisopropylindenyl. manganese tricarbonyl; 1,2,3,4,5,6,7-heptamethylindenyl manganese tricarbonyl; S-phenylindenyl manganese tricarbonyl; 3(2-ethylphenyl) indenyl manganese tricarbonyl; etc.

Examples of compounds havingthe configuration of structure III above are fluorenyl manganese tricarbonyl; S-ethylfluorcnyl manganese tricarbonyl; 4-propylfluorenyl manganese t'ricarbonyl; 2,3,4,7-tetramethylfluorenyl manganese t'ricarbonyl; and the like.

Examples of compounds having the configuration of structure IV above are 4,5,6,7-tetrahydroindenyl manganese tricarbonyl; 3-methyl-4,7-dihydroindenyl manganese tricarbonyl; 2-ethyl-3-phenyl-4,5,6,7-tetrahydroindenyl manganese tricarbonyl; 1,2,3-,4,5,6,7,8-octahydrofluorenyl manganese tricarbonyl; 1,4,5,8-tetrahydrofluorenyl manganese tricarbonyl, and the like.

The preparation of the compounds of this invention is accomplished by a process which comprises reacting a hydrocarbon cyclomatic manganese compound in which the c'yclomatic group has from 5 to 17 carbon atoms and which embodies five carbons having the general configuration found in cyclopentadiene, such as bis- (cyclopentadienyhmanganese, with carbon monoxide at pressuresof substantially zero to about 50,000 p.s.i. and at temperatures of substantially zero to about 350 C.

The cyclomatic manganese compound which is used in the preparation of the compounds of our invention is preparedby the reaction of a cyclomatic alkali metal compound with a manganese salt of an organic or inorganic acid, preferably the respective manganous salts. Examples of these manganese salts are manganous acetate, manganous benzoate, manganous carbonate, manganous oxalate, manganous lactate, manganous nitrate, manganous phosphate, manganie phosphate, mangnous sulfate, manganous fluoride, manganous chloride, mang anous bromide, and manganous iodide, and the like. In addition, manganese salts of B-diketones, suehwas tris- 2,4-pentanedione)manganese and tris(2,4-hexanedione) manganese may also be employed, as well as manganese salts of p-keto esters, such. as the manganese salts of ethylacetoacetat'e, and the like. An example of this is the reaction of cyclopentadienyl. sodium with manganous halide to give bis (cyclopentadienyllmanganese. Cyclomatic alkali metal compounds are also reacted with naturally occurring manganese ores, such as mauganosite (M nO), manganese dioxide (MnO manganic sesquioxide (Mn-Q mnganous sulfide (MnS), manganic sulfide (MnS rhodochrosite (MnCO and the like, to give bis(cyclomatic)manganese compounds such as bisfimethylcyclopentadienyl')manganese, etc. The cyclomatic manganese compound canbe separated from the reaction mixture by distillation or other conventional methods and subsequently reacted with carbon monoxide, either with or without asolvent, or, the reaction mixture containing the cyclomatic manganese compound is subjected to reaction with carbon monoxide as above to give a reaction product containing the cyclomatie manganese tricarbonylcompound such as, for example, cyclopentadienyl manganese tricarbonyl. The latter can: then be separated by conventional methods.

' The cyclomatic alkali metal compound used in the" preparation of our compounds is synthesized by reaction of a cyclornatic compound with an alkali metal or alkali metal amide. To the cyclomatic alkali metal. compound, which is preferably contained in a suitable solvent such as tetrahydrofuran, is added the manganous salt and the resulting cyclomatic manganese compounds are reacted with carbon monoxide either in the reaction: mixture or else in the pure state after separation as indicated above.

A particularly preferred embodiment of our invention comprises the preparation of methylcyclopentadienyl manganese tricarbonyl' by reacting di(methylcyclopentadienyl ymangauese with carbon monoxide at a tempera the like. The product can also be separated from the reaction mixture by steam distillation or selective solvent extraction. The solvent maybe removed from the product by fractional distillation and the product further purified by fractional distillation or sublimation- The method. of preparation is further illustrated in the examples below.

EXAMPLE I Cyclopentadienyl manganese tricarbonyl A reaction vessel equipped with means for charging. and discharging liquids and solids, gas inlet and outlet means, temperature measuring devices, heating and cooling means, means for agitation, and means for condensing vapors, was flushed with prepurified nitrogen. To the flask were then added 400 parts of tetrahydrofuran and 23 parts of sodium dispersed in 23 parts of mineral oil. An atmosphere of nitrogen was maintained in the reaction vessel throughout the run. The vessel was cooled to 10 C. and 66.7 parts of freshly-distilled cyclopentadiene was added in small increments with agitationwhile maintaining the temperature below 15 C. After the addition of the cyclopentadiene, the temperature was allowed to rise to 23 C. over a period of about two hours when the completion of the formation of the sodium cyclopentadiene was evidenced by the cessation of hydrogen evolution. To this solution of cyclopentadienyl sodium in tetrahydrofuran was added 63 parts ot anhydrous manganous chloride. The mixture was heated and maintained at reflux temperature for 20 hours. At the end of this time, the solvent was removed by dis tillation under. reduced pressure and the product purified by sublimation at a pressure of about 2 mm. of mercury at about C., producing 48.64 parts, 52.5 percent yield, of lustrous, brown-black bis-(cyclopentadienyl) manganese crystals. Analysis of the product showed it to contain 64.9 percent carbon and 5.44 percent hydrogen, corresponding to the formula (C H Mn, calculated 64.9 percent carbon and 5.41 percent hydrogen. The bis(cyclopentadienyl)manganese oxidizes readily in air and should, therefore, be kept in an inert atmosphere, such as nitrogen.

The bis(cyclopentadienyl)manganese together with 88 parts of diethylether was charged under a nitrogen atmosphere to a pressure resistant vessel which had been flushed with prepurified nitrogen. The vessel was equipped with gas inlet and outlet valves, temperature and pressure measuring devices, heating and cooling means, and means for agitation. The vessel was pressured with carbon monoxide to 1975 p.s.i. at 26 C. and then the temperature was slowly raised to 158 C. The reaction between the CO and (C H Mn was conducted at a temperature within the range of 22 C.l'58 C. and at a pressure ranging from 11-60 to 2800 p.s.i. for a period of 7 hours. The excess CO was then released below 30 C. and the reaction mixture, a yellow-brown slurry, was removed from the vessel. The solids were removed by filtration and the residue washed with ether to remove the last traces of product which is soluble in the ether. The ether was then distilled off at reduced pressure and the product purified by sublimation. It consisted of a yellow air-stable, water-insoluble solid having a melting point of 77 C. It is readily soluble in most hydrocarbons and organic solvents including benzene, hydro- 7; carbon fuels, lube oils, hexane, ether, alcohol, acetone,

etc. Analysis showed it to contain 47.2% C, 2.46% H, and 26.9% Mn, C H Mn(CO) calculated 47.0% C, 2.47% H, and 26.9%

Mn. The yield was 75.4 percent based on the amount.

of dicyclopentadienyl manganese intermediate obtained, or 39.2 percent based on the amount of MnCl employed.

In another run, the procedure of Example I was repeated except that the intermediate (C H Mn was not isolated. The reaction mixture containing this interme-- EXAMPLE II Methylcyclopentadienyl manganese tricarbonyl The procedure of Example I was followed employing 400 parts of tetrahydrofuran, 23 parts of sodium dispersed in 23 parts of mineral oil, 80 parts of freshly-distilled methylcyclopentadiene, and 63 parts of powdered MnCl containing 3.11 percent water. The manganous chloride was added to the methylcyclopentadienyl sodium solution at a temperature of 20 C. After maintaining the mixtureat reflux temperature for two hours, the intermediate bis(methylcyclopentadienyl)manganese was separated by distillation at reduced pressure under nitrogen. It was a viscous, reddish-brown liquid which crystallized on I standing. Analysis showed it to contain 66.7 percent car-' bon and 6.54 percent hydrogen, corresponding to the formula (C H Mn; calculated 67.6% C and 6.62% H.

The yield was 84.3 percent based on the amount of MnCl employed. The

should not be exposed to oxygen of the atmosphere.

The intermediate was transferred under nitrogen to the pressure resistant vessel and the vessel charged with CO and heated from about 22 C.148 C. at 680 to 2175 p.s.i.g. The reaction was essentially completed in about 1 hour as indicated by the cessation of CO uptake. The vessel was then cooled, the product mixture removed, and the resultant product-methylcyclopentadienyl manganese tricarbonyl-purified by fractional distillation at reduced pressures. The product distilled at 106.5 C. at a pressure of 12 mm. of mercury, and was a yellow-orange liquid having a freezing point of 0.75 C., a refractive index (n of 1.5873, and a density (1 of 1.3942. It has a vapor pressure ranging from 8 mm. at 100 C. to 360.6 mm. at 200 C. It is readily soluble in hydrocarbons and most organic solvents, including hexane, hydrocarbon fuels such as gasoline and diesel fuels, lubricating oils, alcohols, ether, acetone, ethylene glycol, etc. Analysis of the compound showed 24.7 percent manganese, 49.9 percent carbon, and 3.16 percent hydrogen; calculated 25.2% Mn, 49.6% C, and 3.21% H. The yield was 77.8 percent based on the amount of bis(methylcyclopentadienyl) manganese used and 65.6 percent based on the amount of MnCl employed. A good yield is also obtained when the process of Example II is carried out using a pressure of carbon monoxide of substantially 10 p.s.i.g.

The process of Example II was repeated except that the intermediate reaction mixture was reacted with carbon monoxide at a temperature of substantially 34 C. and a pressure of about 1195-2000 p.s.i. The yield of methylcyclopentadienyl manganese tricarbonyl was 61.3 percent based on the amount of mangauous chloride employed.

A variation of Example II, by which the same product is prepared, consists of adding methylcyclopentadiene to a mixture of manganous chloride and sodium dispersed in mineral oil and then reacting the mixture thus obtained with carbon monoxide to get a good yield of methylcyclopentadienyl manganese tricarbonyl.

corresponding -tothe. formula;

bis (methylcyclopentadienyl) manganese is spontaneously combustible and, therefore,

10 EXAMPLE III Methylcyclopentadienyl manganese tricarbonyl Carbon monoxide was reacted with bis(methylcyclo pentadienyl)manganese in tetrahydrofuran at substantially 170 C. and 400-500 p.s.i. over a period of about 5.75 hours. The reaction mixture was then discharged into about 800 parts of water and steam distilled, taking off the tetrahydrofuran first and the product next. The product was separated from the water layer and purified by distillation at reduced pressures. Based on the amount of MnCl employed, 54.2 percent of methylcyclopentadienyl manganese tricarbonyl product was obtained.

Good yields are also obtained when pressures of car-' bon monoxide below one atmosphere are employed.

EXAMPLES IV Ethylcyclopentadienyl managanese tricarbonyl Ethylcyclopentadiene was prepared by reaction of cyclopentadienyl sodium with ethyl bromide. Then, ethylcyclopentadienyl manganese tricarbonyl was pre pared according to the process described in ExampleI. The product had a refractive index of 1.5760 and a boiling point of 48 C.49 C. at 0.3 mm. of mercury. On analysis it was found to contain 52.1 percent carbon, 4 percent hydrogen, and 22.7 percent manganese, corresponding to the formula C H Mn(CO) calculated 51.8% C, 3.88 H and 23.0% Mn.

EXAMPLE V Allylcyclopentadienyl manganese tricarbonyl The procedure of Example IV is followed using allylchloride in place of ethyl bromide, potassium in place of sodium, and tris (2,4-pentanedione)manganese in place of manganous chloride. A good yield of allylcyclopentadienyl manganese tricarbonyl is obtained. Good yields are also obtained when lithium is used in place of potassium.

EXAMPLE VI Phenylcyclopentadienyl manganese tricarbonyl Phenylcyclopentadine, obtained by treating cyclopentenone with phenyl lithium to give 1-phenyl-2-cyclopentene-l-ol which upon distillation yields phenylcyclopentadiene, is reacted with sodium according to the procedure described in Example I to give phenylcyclopentadienyl sodium. This is reacted with manganese bromide I to give bis(phenylcyclopentadienyl)manganese and the 50 reaction mixture contacted with CO at a pressure of substantially 300 p.s.i. and a temperature of substantially 200 C. to give phenylcyclopentadienyl manganese tricarbonyl in good yield.

EXAMPLE VII The procedure of Example I was followed using indene in place of cyclopentadiene. Upon reaction of the bis- (indenyl)manganese without separation from the reaction mixture with carbon monoxide at a temperature of substantially C. and a pressure of substantially 3000 p.s.i. over a period of 3.5 hours, followed by an ether extraction of the product from the reaction mixture,-a

good yield ofindenyl manganese tricarbonyl Wasob-. tained.- The product consisted of orange-colored crystals having a melting point of 50 C'-51 C. and; was solua Ible in ether, benzene, petroleum hy rocatbons, andiacez '11 tone. Analysis showed-.itto-contain 57.0 percent carbon and 2.93 percent hydrogen, corresponding to the general formula CH Mn(CO) wherein C H denotes anindenyl radical;.calculated 57.7% C and 2.76% H.

EXAMPLE IX 1,2,3,4,5'-pentamethylcyclopentadienyl manganese tricarbonyl The. procedure of Example IIv isemployed. using 136 parts of 1,2,3,4,5-pentamethylcyclopentadiener and. 108. parts of manganous, bromide (MnBr Lithium, was used in place of sodium. The intermediate reaction mixture is. reacted with carbon monoxide at less than one atmosphere and at 300 C. to give a good'l yield of 1,2,3,4,5-pentamethylcyclopentadienyl manganese tricarbonyl.

Good results are. also obtained when Mnl isused in place of'MnBr EXAMPLE X Octylcyclopentadienyl manganese tricarbonyl- EXAMPLE XI I-na-phthyl-Z-etliylcycli2pentadienyl manganese v tricarbonyl The procedure of Example II is followed using 222 parts of 1-naphthy1-2-ethylcyclopentadiene and 63 parts of manganous fluoride. The reaction mixture containing bis(1-naphthyl-2-ethylcyclopentadienyl)manganese is reacted with carbon monoxide at a pressure of .20 lbs. and at a temperature of 78 C. to give a good yield of 1-naphthyl-2-ethylcyclopentadienyl manganese tricarbonyl.

EXAMPLE XII- 1,3;4,7 telramethylindenyl manganese tricarbonyl,

The procedure of Example II-is'carried out employing 172 parts of 1,3,4,7'-tetramethylindene and 86 parts of rnanganous acetate. The reaction mixture containing-thebistgl,3,4,7-tetramethylindenyl)manganese isreacted withwith CO at a pressure of 1000 psi. and at a temperature of 20 C. to give a good yield of 1,3,4,7-tetramethylindenyl manganese tricarbonyl.

EXAMPLE XIII 3-cycl0hexylindenyl manganese tricarbonyl- Following the. procedure of Example 11,. 192. parts of- 3-cyclohexylindene is reacted with 150 parts of manga, nous benzoate and the. reaction mixture containing bis- (3-cyclohexyliudenyl)manganese is reacted with carbon monoxide at a pressure of 10,000 p.s.i. and a temperature. of 0 C. to give 3cyclohexylindenylmanganese tricarbonyl;

' EXAMPLE XIV 4;5,6,7 tetrahydr0indenyl manganese tricarbonyl In-the-process of- Example II- 120 parts of 4,5,6}7- tetrahydroindene isreacted with 72 parts of manganous oxalate; The intermediate reaction-mixture is reacted with carbon monoxide at a pressure of 20,000*p.s.i= and a'temperatureof 220 C. to give a-good yield of 4,536,7-

tetrahydroindenyl manganesetricarbonyl; i

50,000p.s.i. and higher.

12 EXAMPLE XV 23,45 ,6,7, 9 octahydrofluorenyl manganese tricarbonyl The. procedure of Example II is. followed in reacting 174' parts of 1,2,3,4;5;6,7,8-octahydrofluorene with 76' parts of 'manganous sulfate and the reaction mixture containing bis(1;2,3,4,5,6,7,8-octahydrofiuorenyl)manganese is reacted with carbon monoxide at a pressure of 50,000

p.s.i.. and a; temperatureof 350 C. to give a good yield.-

of 1,2}3f,,4,5,,6,7,8.- octahydrofluorenyl. manganese. tricarcarbonyl.

EXAMPLE XVI 1',8 diethylflu0renyl manganese tricarbonyl EXAMPLE XVH Fluorenyl manganese tricarbonyl procedureof Example II. is followed in reacting 166 parts. of.fluorene with 59 parts of manganous phosphate, andthereactionmixture, containing bis(fluorenyl).

manganeseis reacted with-carbon monoxide at a pressure.

of. substantially- 50.00 p.s.iat a. temperature of substantially 200 C. to givea good yield of fluorenyl manganese tricarbonyl.

The temperature. of. the steps in our process may be.

varied. For. example, the. reaction of sodium with the:

cyclomatic compound can be performed at temperatures up to the boiling point of the cyclomatic compound. For dicyclopentadiene, this is about 175 C. at which point cracking to the. monomer occurs and. the latter reacts with sodium to form cyclopentadienyl sodium. A. pro-- ferred-range of temperatures is from about 10 C. to about 65 C. when conducting the reaction in a solvent,

such as. tetrahydrofuran. The upper temperature repre.--

The man.

sents the. boiling point of tetrahydrofuran. ganese salt, i.e., MnCl MnBr or MnSO etc may be added to the. alkali metal cyclomatic compound at tern-- peratures-ranging from -20 to 65 C. and higher, de-

pending on the boiling, point of the solvent, and since:

there is no great temperature rise upon addition oil the manganese halide, the. temperaturelimits are not critical. However, we. prefer to conduct. this reaction at a tempera.- ture' of from 205-65. C. in order tocut down the time. of reaction. The reaction mixture need not be refluxed; however,.reflux:periods up to. 16. hours have been em? ployed. with. good. success.

Thetemperatureat which CO reacts with the intermediate:bis(cyclomatic).manganesecompound varies from 0?" C. to about: 350 C. with the rate of reaction increasing as tlie temperature is increased. The temperature of the reaction depends. on the freezing point of the intermediatebis(cyclomatic)manganese compounds or the freezing pointof 'thesolvent employed, if any, and alsoupon the pressure. An especially preferred range of tempera turesfor the. carbonylation of the cyclomatic manganese intermediate-is from 20 t0 about 200 C., as temperatures. withirrthis range are easily maintainable and good yields are realized.

Carbon-monoxide reacts with the cyclomatic manganese.

compound to-form the-cyclomatic manganese tricarbonyl' compounds-at pressures below atmospheric to as high as However, a preferred range of pressures at which the reaction can be conducted is from about l0-toabout 1 0,000 p.s.i.g., as no great advantage is gained'by going to higher pressures, and at pressures below about 10-p.s.i.g. the time required'to ob- -"tain a given amount of product is considerably lengthened. An especially preferred range of pressures for the carbonylation of cyclomatic manganese compounds according to this invention is from 20 to about 1000 p.s.i., as it is found that this reaction proceeds quite readily and can be conducted in moderate-pressure apparatus.

The time of reaction of any part of the processes depends on temperature and pressure conditions, etc., and vary over a wide range. For instance, the reaction of sodium with cyclopentadiene is practically instantaneous and the rate of admixture of reactants depends on the efliciency of cooling. Therefore, the time of reaction can vary from several minutes to a few hours, such as 4 hours. The time for reaction between the cyclomatic manganese compound andCO can also vary within wide limits, depending on temperature, pressure, and the extent of reaction that is desired. Thus, at high pressures and temperatures the reaction goes to completion in a matter of a few minutes, while at lower pressures and temperatures it may be advantageous to keep the CO in contact and in agitation with the cyclomatic manganese compound for a period of 1-10 hours.

' Solvents other than tetrahydrofuran, ether, and benzene were used in other runs which are not included in the illustrative examples given hereinabove. Such other solvents, or mixtures thereof, which were employed are nbutyl ether, dioxane, toluene, and dimethyl ether of ethylene glycol. Also, as indicated above, solvents are not essential for the conduction of the reaction of carbon monoxide with the cyclomatic manganese compounds to produce the cyclomatic manganese tricarbonyl compounds.

The alkali metals used in our process to make the metal derivatives of the cyclomatic compounds which are thenreacted with a manganese metal or compound to make the cyclomatic manganese compound include lithium, sodium, potassium, rubidium, and cesium. Metals other than the alkali metals that can be used are the group IIA metals such as beryllium, magnesium, calcium, strontium, and barium, and the group 113 metals such as zinc and cadmium. In the case of polyvalent metals, the compounds may contain halogen such as the Grignard reagent in the case of magnesium.

The product recovery procedure employed depends on the method of preparation and on the compound synthesized. When reacting CO with pure bis(cyclomatic)- manganese, the product may be separated and purified by fractional distillation or sublimation at reduced pres-- sures as illustrated hereinabove. Another method of separation is to steam distill the reaction mixture, separate the organic product layer from the aqueous layer and further purify the product by fractional distillation at reduced pressures. This latter method is employed with good success when the carbon monoxide is reacted with the intermediate from its reaction mixture. Another method of separation involves extraction of the cyclomatic manganese tricarbonyl compound from the reaction mixture with selective solvents such as benzene, ether, etc. and the separation of the product from the solvent by fractional distillation followed by further purification consisting of either fractional distillation, sublimation, or both.

a In the above examples the cyclomatic alkali metal compound Was prepared by reaction of the cyclomatic compound with a dispersionof the alkali metal in mineral Anumberlof othermethods for the preparation of these compounds may be employed however. For example, sodium cyclopentadieue has been prepared by the reaction of cyclopentadiene with sodamide.

In the above examples nitrogen was employed as the inert atmosphere to prevent oxygen from coming in contact with the reactants. Other inert gases may also be used, e.g., argon, methane, ethane, propane, and other hydrocarbons and vapors of the solvents employed in the reaction.

Our compounds can be employed with hydrocarbon fuels and lubricating oils for improving operating characteristics of reciprocating, spark fired, or compression ignition engines. The compounds can be used in fuels and lubricating oils by themselves or together with other additive components, such as scavengers, deposit modifying agents containing phosphorus and/or boron, and also other antiknock agents, such as tetraethyllead, etc.

The compounds can be added directly to the hydrocarbon fuels or lubricating oils and the mixture sub jected to stirring, mixing, or other means of agitation until a homogeneous fluid results. Alternatively, the compounds of our invention may be first made up into concentrated fluids containing solvents, such as kerosene, toluene, hexane, and the like, as well as other additives such as scavengers, antioxidants and other antiknock agents, e.g., tetraethyllead. Still other components that can be present are discussed more fully hereinbelow. The concentrated fluids can then be added tothe fuels.

Where halohydrocarbon compounds are employed as scavenging agents, the amounts of halogen used are given in terms of theories of halogen. A theory of halogen is defined as the amount of halogen which is necessary to react completely with the metal present in the antiknock mixture to convert it to the metal dihalide as, for example, lead dihalide and manganese dihalide. In other words, a theory of halogen represents two atoms of halogen for every atom of lead and/or manganese present.- In like manner, a theory of phosphorus is the, amountof phosphorus required to convert the lead present to lead orthophosphate, Pb (PO that is, a theory of phosphorus based on lead represents an atom ratio of two atoms of phosphorus to three atoms of lead. When based on manganese, a theory of phosphorus likewise represents two atoms of phosphorus for every three atoms of manganese, that is, sufliceint phosphorus to convert manganeseto manganese orthophosphate, Mu (PO The following isillustrative of fluids and fuels containing our new compounds.

To 1000 gallons of a commercial fuel having an initial boiling point of F. and a final boiling point of 406 F. is added 59.4 grams of methylcyclopentadienyl manganese tricarbonyl, C H Mn(CO) and the mixture subjected to agitation until the additive is distributed evenly throughout the fuel, in an amount equivalent to 0.015 gram of manganese per gallon fuel.

Fuels containing mixtures of two or more cyclomatic manganese tricarbonyl' compounds, such as mixtures of cyclopentadienyl manganese tricarbonyl and methylcyclopentadienyl manganese tricarbonyl, are prepared in a similar manner.

To 11 parts of methylcyclopentadienyl manganese tricarbonyl is added 5 parts of ethylene dichloride and the mixture agitated until a homogeneous fluid results. The manganese to chlorine atom ratio in this fluid is 1:12 and represents 6 theories of halogen based on the manganese.

In like manner, a fluid is prepared comprising indenyl .manganese tricarbonyl and ethylene dibromide in which the manganese to bromine ratio is 1:6, representing 3 theories of bromine based on the manganese. Likewise, a fluid containing ethylcyclopentadienyl manganese tricarbonyl, ethylene bromohydrin, and 2,3-dichloro-l,4 dimethylbenzene is prepared in such proportions that for every 75 atoms of manganese, there are one atom of bromine and two atoms .of chlorine, representing the total of 0.02 theory ofv halogen.

The abovefluids are added to hydrocarbon fuels in amounts so as toprovide improved fuels containing 0.015 gram, 0.03 gram, 6 grams and 10 grams of manganese per gallon.

Other fuels and fluids are prepared in the same manner as illustrated hereinabove. which contain other deposit-f modifying agents, such as boric acid, borate esters, boron-- ic. esters. etc; Likewise. lubricating oils. containingfrom about 0.1. to about 5. weight. percent manganese. in, the form. of the cyclomatic manganese, tricarbonyl compounds. of. this. invention. are prepared, and. these lubricating-oils, when used in reciprocating engines, are found. to. have abeneficial eifect on engine cleanliness. and. in the I'QdllC! tion, of combustion chamber deposits.

In, order to illustrate some. of the; advantages, of. em: ploying the new cyclomatie manganese tricarbonyl com: pounds as antiknock agents in fuels, a; number of. tests were conducted in which a singlercylinder QFR knock test; engine. was operated on fuels, containing varying amounts of the compounds. of this; invention... The test method employed was that described. in est. procedure. 11-90841 contained in the,1952 editionof/ASTM. Manual of. Engine. Test. Methods? for rating fuels.- Theresultsofi a number of tests. in- Wbich fuels .were, employed containing only the. compounds. of this invention and, compounds, of this invention,together-twithleamand also. fuels containing bis(cyclopentadienyl)iron andiron care bonyl are contained in Table 1 below.

The .antiknock value of the. fuels asdeterminedby the. ratings, are given in octane, numbers. for figures. below 100 and in Army-Navy performance. numbers. for values above 100. Performance numbers. aredetermincdby operating an engine on isooctane wherein. the intake. manifold ressure is supercharged. by. means of. a fan. until a knock is detected. The power output of the, motor under these conditions is, notedand' the value for pure. isooctane fuel is taken as baseline, ,andequal to.-1 00. When. a fuel. other thanisooctane is to b.e.rated..the. same. procedure is followed. The power outputof the, test. fuel is then compared to the power output .ofpure, isooctane.

fuel. Thus, if a fuel results. in.105. percent as much power output of an. engine. as. when that engine, oper-- ated on isooctane under these. conditions, the test fuel.

issaid tohave. a performance-number of 1.05...

Table-sL-Improvement in the antiknock quality. of a 77.2 octane number fuel PART I" C5H5Mn(C0)s g. Mn g. Pb-as Octane g. per gal. per gal. TEL/gal. Number 0. 0. 0 7.7. 2; 1. 85v 0. 5, 0. 86. 3 3. 71 1. 0 0 89. 4 7. 42 2. 0. 0 93; 2; 11. 13 3. 0 0. 96. 16; 7' 4. 5 0 98. 8 0 0 1.. 06 85.6 1. 85 0., 5 1.06v 89. 3 3. 71 1:0 1. 06- r 91.7 7'. 42 2. 0 1. 06 96. 7 11. 13 3.0 1. 06 98.0 0 0 3. 17 00. 0 1. 85 0. 5 3. 17 95; 5 3. 71 1. 0 3. 17 96. 6 7. 42 2. 0 3. 17 98. 8 11. 13 3.0 3.17 100. 0

PART II C H1Mn(CO); g. Mn g. Pb-as' Octane it. per al. per ca TEL/c Number.

From the above it is seen that one gram of manganese per gallon in, the form. of cyclopentadienyl manganese tricarbonyl increases the. octanevalucof. the fuelfrom 77.2 to 89.4, an. incr asecf 1.2.2 octane. number un ts,

An e en. greater adyantageis obse ed; n. e. use 2- he. eyclomatic manganese carbonyl compounds of i n-. vention; when employed in conjunction with fuels, containing alkyllead compounds, such as tetraethyllead. For example, when 3 grams of manganese in the form of cyclopentadienyl manganese tricarbonyl is, added per gallon to a fuel containing one milliliter of tetraethyllead (1.06 grams of Pb) per gallon, theoctane numberof the. fuel is found to. be 98.9 as. compared to 85.6 octane. numbers of a fuel containing only the one milliliter of tetraethyllead. This represents an increase of 13.3. oc-. tane numbers. This amount of manganese as-methylcye clopentadienyl manganese tricarbonyl increases the octane value by 13.6 units.

Other important uses of the cyclomatic compounds of the present invention includethe use, thereof as chemi; cal intermediates, particularly in the. preparation of metal and metalloid containing polymeric, materials, In addi. tion, some of the cyclomatic derivatives of this, inven-. tion can be used in the manufacture of medicinals and; other therapeutic materials, as well as agricultural chemicals such as, for example, fungicides, insecticides, defoliants, growth regulants, and so. on.

Having fully described the novel cyclomatie derivatives of the present invention, the need therefor, and the best methods devised for their preparation, we do. not intend that our invention be limited except within the spirit and scope of the appended. claims.

We claim:

1 A process for the preparationof a cyclopentadienyl; manganese tricarbonyl having the general formula wherein A is a cyclopentadienyl hydrocarbon group hav ing from 5 to 17 carbon atoms and'wherei-n the cycle pentadienyl group is bonded to the manganese through the carbons of the cyclopentadienyl ring, comprising reacting carbon monoxide with a di-cyclopentadienyl manganese in which there are two cyclopentadienyl groups each containing from 5 toabout 17 carbon atoms and each having a cyclopentadienylring bonded directly to the manganese.

2. The process of claim 1 wherein the carbon-mom oxide is employed at pressures of from 0 to about 50,000 p.s.i. and the reaction is conducted at temperaturesof from about 0 C. to about 350 C.

3. A process for the preparation of a cyclopentadienyl manganese tricarbonyl having the general formula AMn(CO) wherein A is a eyclopentadienyl hydrocarbon group hav ing from 5 to 17 carbon atoms and wherein the cyclm pentadienyl group is bonded to the manganese through the carbons of the cyclopentadienyl ring, comprising reacting a manganese salt with a cyclopentadienyl alkali metal in which the cyclopentadienyl moiety is a hydroe carbon group having from 5 to 17 carbon atoms and containing a cyclopentadienyl ring bondeddirectly to the alkali metal to form a diecyclopentadienyl manganese. and thereafter reacting said di-cyclopentadienyl manganese with carbon monoxide.

4. A process for the preparation of a cyclopentadienyl hydrocarbon manganese. tricarbonyl compound having the general formula AMn(CO) wherein A is a cyclopentadienyl hydrocarbon grouphavving from 5 to about 17 carbon atoms and whereincthe.

5. A process for the preparation of cyelopentadienyl manganese tricarbonyl which comprises reacting di(cyclopentadienyhmanganese with carbon monoxide at pressures from 0 to about 50,000 p.s.i. and temperatures from 0 to about 350 C.

6. A process for the preparation of methyleyclopentadienyl manganese tricarbonyl which comprises reacting di(methyicyclopentadienyl)manganese with carbon monoxide at pressures from 0 to about 50,000 p.s.i. and temperatures from 0 to about 350 C.

References Cited in the file of this patent Fischer et a1.: Zeit. Naturforschg., 8b, 444-445 (1953).

Fischer et a1.: Zeit. Naturforschg., 9b, 618 (1954). 

1. A PROCESS FOR THE PREPARATION OF A CYCLOPENTADIENYL MANGANESE TRICARBONYL HAVING THE GENERAL FORMULA 